In recent years, a user terminal (so-called dual terminal) including a cellular communication unit and a wireless LAN communication unit is becoming widely used. Further, the number of wireless LAN access points operated by an operator of a cellular communication system increases.
Therefore, in 3GPP (3rd Generation Partnership Project) which is a project aiming to standardize a cellular communication system, consideration is given to introduction of a technology capable of strengthening linkage between a cellular communication system and a wireless LAN system (see Non Patent Document 1).